JPH0143345Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a piston stopping mechanism that prevents a secondary piston from retreating more than a predetermined amount in a tandem master cylinder for an automobile in which two pistons, front and rear, are fitted into the same cylinder.

A conventional example will be explained based on FIG. 1, and the same or substantially the same parts as in FIG. 3, which will be described later, are given the same reference numerals. Secondary piston 1
As a means to prevent the cylinder from moving backward more than necessary, a set bolt 8 is screwed in from outside the cylinder body 4 at the lower side where the reserve tank 5 does not exist, and its tip is exposed into the cylinder body 4. In this case, the gasket 1 that can be inserted into the threaded part of the set bolt 8
2 was required, and the fact that 12 seals were required gave rise to concerns about leaks.

Another conventional example will be explained based on FIG. 2, and the same or substantially the same parts as in FIG. 1 and FIG. 3, which will be described later, are given the same reference numerals. As a means to eliminate the fear of leakage in FIG. 1, there is also a system in which a stopper 9 is provided in place of the set bolt 8 on the side that passes into the reserve tank 5. However, since the stopper 9 was fixed to the circumferential wall of the cylinder body 4, it was necessary to remove the reserve tank 5 when disassembling the cylinder body 4, and some reserve tanks 5 were of a fixed type that could not be removed, making maintenance difficult. This resulted in inconvenient restrictions on handling.

FIG. 3 shows an embodiment of the present invention, and the following description will be made based on the same figure. Components that are the same or substantially the same as those in FIG. 1 or 2 are given the same reference numerals.

A continuation of the cylinder body 4 and the reserve tank 5 in which a recess 1 formed on the outside of the cylinder body 4 and a convex portion 2 provided on the lower side of the reserve tank 5 fit together via an elastic bushing 3 made of rubber or the like. At this point, a notched hole 14 is provided in the convex portion 2, and a pin 6 is press-fitted into the convex portion 2, so that the tip of the pin 6 protrudes into the cylinder body 4, and the portion of the pin 6 that passes through the cylinder body 4 is formed as a hole with a larger diameter than the pin 6. An oil supply hole 7 is formed on the peripheral side of the secondary piston 13. Note that a return spring 1 is installed between the bottom 19 of the cylinder hole and the secondary piston 13.
8 has been reduced. In addition, the presence of a replenishing oil passage 10 and an oil replenishing hole 11 from the reserve tank 5 to the cylinder body 4 at this connection part is an existing structure, and an oil refilling hole on the circumferential side of the secondary piston 13 is also required, but the present invention According to the invention, since the oil supply hole 7 is formed on the outside of the pin 6, it is not necessary to separately drill the oil supply hole. In addition, the pin 6 can be attached and detached without removing the reserve tank 5, which makes disassembly and maintenance of the master cylinder convenient, eliminates damage to the connecting parts of the bush 3, etc., and prevents the cylinder body 4 from being damaged.
Since the pin 6 penetrating the wall is installed at the internal passage to the reserve tank 5, there is no fear of oil leakage.

FIGS. 4A to 4E show various shapes of the pin 6. In addition, as shown in FIG.
is a lock hole type, and a photographing piece 15 and a locking piece 16 are provided above and below the pin 6, and when the pin 6 is inserted into the notch hole 14 and rotated with strong force, The hemispherical protrusion 17 and the pin 6 are elastically deformed, the locking piece 16 climbs over the protrusion 17, and the locking piece 16 is fitted between the two hemispherical protrusions 17, 17, resulting in the state shown in FIG. Therefore, it is also possible to configure the pin 6 to prevent blind rotation.

[Brief explanation of drawings]

Figures 1 and 2 are cross-sectional views showing the conventional structure;
FIG. 3 is a sectional view of an embodiment of the present invention, and FIGS. 4A to 4A are diagrams showing various examples of pin shapes. FIG. 5 is an exploded perspective view of a partially modified example, and FIG. 6 is a bottom view of the same assembled state. 1...Concave portion, 2...Convex portion, 3...Button, 4
... Cylinder body, 5 ... Reserve tank, 6
...Pin, 7...Oil supply hole, 8...Set bolt,
9... Stopper, 10... Supply oil line, 11...
Replenishment hole, 12... Packing, 13... Secondary piston, 14... Notch hole, 15... Photograph piece, 16... Latching piece, 17, 17... Protrusion, 18
... Return spring, 19 ... Bottom of cylinder hole.

Claims (1)

[Scope of utility model registration request] A cylinder body 4 in which a concave portion 1 formed on the outside of the cylinder body 4 and a convex portion 2 provided on the lower side of a reserve tank 5 fit together via an elastic bush 3.
At the connecting part between the cylinder body 4 and the reserve tank 5, a notch hole 14 is provided in the convex part 2, and a pin 6 is press-fitted into the convex part 2, so that the tip of the pin 6 protrudes into the cylinder body 4, and the part of the pin 6 that penetrates the cylinder body 4 is inserted into the cylinder body 4. A piston restraining mechanism in a tandem master cylinder, characterized in that an oil supply hole 7 is formed on the circumferential side of the piston as a hole with a larger diameter than that of the oil supply hole 7.